Waddell's Nonorganic Signs in Occupational Low Back Pain Patients

Doctors and researchers are interested in simple, quick, and effective ways to determine which low back pain patients are at higher risk for persistent symptoms and disability. Waddell's nonorganic signs have previously been established to evaluate eight behavioral signs that imply a patient is poorly coping in proportion to the physical condition of their back. Low back pain is of course a concern in occupational medicine—since it occurs so regularly and induces costs to employers. This study appraised if Wadell's nonorganic signs in occupational acute low back pain patients predicted a longer time before return to work.

The authors evaluated 55 acute low back pain patients. They defined the diagnosis of "acute" if the pain was the first episode in one year, and present during the intake for less than 10 weeks. Of the 55 subjects, 41 were found without signs, and 14 had one or more of Wadell's nonorganic signs. The table below indicates the distribution of signs among the 14 subjects.

The Signs

Number Exhibiting

Percentage Exhibiting

Simulated axial loading

11

78.6%

Simulated rotation

10

71.4%

General overreaction to examination

8

57.1%

Superficial tenderness

8

57.1%

Regional weakness

4

28.6%

Widespread, nonanatomic pain

2

14.3%

Regional sensory deficit

1

7.1%

Distracted straight leg raising

0

0.0%

The authors stress that, "Patients exhibiting any of Waddell's sign's without an otherwise nonfocal examination had the absence of organic findings positively reinforced." Furthermore, all recovering patients stayed in the work setting and performed modified work tasks; they returned to their regular job when released without restrictions. The authors suggest the modified work arrangement helped patients stay active and supported in a work environment.

Patients without signs returned to their full duties in approximately 15 days. Those with Waddell's nonorgnic signs returned four times longer, at 58.5 days. Physical demands, smoking status, age, gender, and previous history were not associated with return to work time. As the table indicates, the best predictors were the categories of "pain with simulated axial loading" and "pain with simulated rotation."

Although the authors declare that their findings display clinical significance of Waddell's in determining predictive factors in acute low back pain patients, they also point out the limitations of the study. The study had a "small sample size, single institution, and single practitioner with unblinded assessment, treatment, and outcomes." In an attached editorial, Steven J. Atlas notes:

"By not blinding the evaluating and treating physician in any manner, the differences observed may simply be caused by well intentioned but biased physician behavior...To me [the findings] highlight the need to pursue research into the early identification of patients at higher risk for persistent, disabling symptoms. Larger, well-controlled studies are needed to determine whether Waddell's signs can prospectively identify such high risk patients. If it can, then treatment strategies are needed to determine whether earlier interventions can result in improved outcomes. "